Cytek Biosciences (CTKB) CTO granted stock options and 227,535 RSUs

Rhea-AI Filing Summary

Cytek Biosciences, Inc. director and Chief Technology Officer Yan Ming reported several equity compensation transactions. On March 10, 2026, Ming received an employee stock option for 120,688 shares of common stock at an exercise price of $4.23 per share, vesting monthly over four years. He also received 227,535 Restricted Stock Units (RSUs), which vest over four years in specified tranches each May 18, August 18, November 18, and March 10 according to the award schedules.

Ming exercised previously granted RSUs covering a total of 25,400 shares of common stock. Of the resulting shares, 7,731 shares were withheld and surrendered to Cytek Biosciences at $4.23 per share to satisfy tax withholding obligations, and the remaining shares increased his direct common stock holdings. After these transactions, Ming directly owned 6,091,933 shares of common stock.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Yan Ming

(Last) (First) (Middle)

C/O CYTEK BIOSCIENCES, INC.

47215 LAKEVIEW BOULEVARD

(Street)

FREMONT CA 94538

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Cytek Biosciences, Inc. [ CTKB ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	CHIEF TECHNOLOGY OFFICER

3. Date of Earliest Transaction (Month/Day/Year)
03/10/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	03/10/2026		M		9,817	A	(1)	6,084,081	D
Common Stock	03/10/2026		F		3,047(2)	D	$4.23	6,081,034	D
Common Stock	03/10/2026		M		7,366	A	(1)	6,088,400	D
Common Stock	03/10/2026		F		2,287(2)	D	$4.23	6,086,113	D
Common Stock	03/10/2026		M		8,217	A	(1)	6,094,330	D
Common Stock	03/10/2026		F		2,397(2)	D	$4.23	6,091,933	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Employee Stock Option (right to buy)	$4.23	03/10/2026		A		120,688		(3)	03/09/2036	Common Stock	120,688	$0	120,688	D
Restricted Stock Units	(1)	03/10/2026		A		227,535		(4)	(4)	Common Stock	227,535	$0	227,535	D
Restricted Stock Units	(1)	03/10/2026		M			9,817	(5)	(5)	Common Stock	9,817	$0	29,460	D
Restricted Stock Units	(1)	03/10/2026		M			7,366	(6)	(6)	Common Stock	7,366	$0	44,203	D
Restricted Stock Units	(1)	03/10/2026		M			8,217	(7)	(7)	Common Stock	8,217	$0	73,958	D

Explanation of Responses:

1. Each Restricted Stock Unit (the "RSU Award") represents a contingent right to receive one share of the Issuer's common stock.

2. Represents the number of shares withheld by and surrendered to the Issuer on March 10, 2026, to satisfy tax withholding obligations that arose in connection with the vesting of the RSU Award.

3. The shares subject to the stock option shall vest over 4 years with 1/48 of the total shares underlying the stock option vesting on April 10, 2026 and each month thereafter until fully vested.

4. The shares subject to the RSU Award shall vest over 4 years with 2/48 of the total shares underlying the RSU Award vesting on May 18, 2026 and each May 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting August 18, 2026 and each August 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting November 18, 2026 and each November 18 thereafter; and 4/48 of the total shares underlying the RSU Award vesting on March 10, 2027 and each March 10 thereafter, until fully vested.

5. The shares subject to the RSU Award shall vest over 4 years with 2/48 of the total shares underlying the RSU Award vesting on May 18, 2023 and each May 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting on August 18, 2023 and each August 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting on November 18, 2023 and each November 18 thereafter; and 4/48 of the total shares underlying the RSU Award vesting on March 10, 2024 and each March 10 thereafter, until fully vested.

6. The shares subject to the RSU Award shall vest over 4 years with 2/48 of the total shares underlying the RSU Award vesting on May 18, 2024 and each May 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting on August 18, 2024 and each August 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting on November 18, 2024 and each November 18 thereafter; and 4/48 of the total shares underlying the RSU Award vesting on March 10, 2025 and each March 10 thereafter.

7. The shares subject to the RSU Award shall vest over 4 years with 2/48 of the total shares underlying the RSU Award vesting on May 18, 2025 and each May 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting on August 18, 2025 and each August 18 thereafter; 3/48 of the total shares underlying the RSU Award vesting on November 18, 2025 and each November 18 thereafter; and 4/48 of the total shares underlying the RSU Award vesting on March 10, 2026 and each March 10 thereafter, until fully vested.

	/s/ Valerie Barnett, Attorney-in-Fact	03/12/2026
	** Signature of Reporting Person	Date
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FAQ

What equity awards did Cytek Biosciences (CTKB) CTO Yan Ming receive?

Yan Ming received an option to purchase 120,688 shares at an exercise price of $4.23 and 227,535 Restricted Stock Units. Both awards vest over four years under detailed schedules tied to specific May, August, November, and March vesting dates.

How many Cytek Biosciences (CTKB) shares does Yan Ming hold after this Form 4?

After these transactions, Yan Ming directly holds 6,091,933 shares of Cytek Biosciences common stock. This figure reflects RSU conversions into common stock and share withholding for taxes, as reported in the non-derivative transaction table for March 10, 2026.

Were Yan Ming’s Cytek Biosciences (CTKB) transactions open-market buys or sales?

No, the filing shows no open-market purchases or sales. The transactions are equity compensation events: option and RSU grants, RSU conversions into common stock, and F-code dispositions where shares were withheld and surrendered to cover tax obligations arising from vesting.

How do Yan Ming’s new Cytek Biosciences (CTKB) RSUs vest?

Each Restricted Stock Unit represents one share of common stock and vests over four years. Portions vest on recurring May 18, August 18, November 18, and March 10 dates, with differing 2/48, 3/48, and 4/48 fractions until the award is fully vested.

What does the F-code tax withholding in the Cytek Biosciences (CTKB) Form 4 mean?

F-code entries show 7,731 shares of common stock were withheld and surrendered at $4.23 per share. These are not open-market sales; they represent shares delivered back to Cytek Biosciences to satisfy tax withholding obligations when RSU awards vested on March 10, 2026.

When do Yan Ming’s Cytek Biosciences (CTKB) stock options expire?

The employee stock option granted to Yan Ming on March 10, 2026 expires on March 9, 2036. The option vests monthly over four years, with 1/48 of the total option shares vesting on April 10, 2026 and each month thereafter until fully vested.